This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The role of Golgi-associated PKA activity is being investigated in terms of signal transmission and the physiology of the organelle. Recent data indicate that Golgi-associated PKA is basically involved in the maintenance of Golgi structural organization which in the case of mammalian cells corresponds to the typical continuous membranous ribbon shape. Thus, Golgi fragmentation occurs following PKA dissociation or inactivation. Indeed, PKA activity is required to achieve complete Golgi reconstruction during biogenesis. In addition, PKA associated to Golgi membranes becomes activated in the course of a normal cell stimulation process by extracelular ligands. This events triggers important adaptative structural changes in Golgi organization including the fusion of cisternae and miscompartmentalization of processing enzymes. These changes could be indicative of alternative routes followed by cargo molecules travelling across the Golgi stacks.